A container refrigeration apparatus for cooling the inside of a container is an example of refrigeration apparatuses for performing a refrigeration cycle. Patent Document 1 discloses a container refrigeration apparatus of this type.
The container refrigeration apparatus disclosed by Patent Document 1 includes a refrigerant circuit connecting a compressor, a condenser, an expansion valve, and an evaporator. The evaporator is provided inside a container. In the evaporator, a refrigerant absorbs heat from the air inside the container to evaporate, thereby cooling the inside air.
A bypass circuit is provided in the refrigerant circuit of the container refrigeration apparatus to supply the refrigerant compressed in the compressor (so-called hot gas) directly to the evaporator without passing through the condenser. Specifically, the bypass circuit includes two bypass pipes, and two open/close valves corresponding to the bypass pipes. Each of the bypass pipes communicates a gas line between the compressor and the condenser and a liquid line between the expansion valve and the evaporator. In the container refrigeration apparatus, heating operation of heating the inside air with the hot gas flowing through the evaporator is performed by using the bypass circuit.
Specifically, the heating operation is performed when the inside air is excessively cooled, and the temperature of the inside air is too low. In the heating operation, heating capability is adjusted in two stages based on the conditions of the two open/close valves. When one of the valves is opened in the heating operation, the hot gas flows through one of the bypass pipes to be fed to the evaporator. Thus, a flow rate of the refrigerant flowing through the evaporator is relatively reduced. Accordingly, the capability of heating the inside of the container is relatively reduced. When both of the valves are opened in the heating operation, the hot gas flows through the two bypass pipes to be fed to the evaporator. Thus, the flow rate of the refrigerant flowing through the evaporator is relatively increased. Accordingly, the capability of heating the inside of the container is relatively increased.